Multi type refrigerating apparatuses have been known conventionally in which a plurality of user side circuit are connected in parallel to a heat source side circuit and user side heat exchangers provided in the user side circuits serve as evaporators to perform a cooling operation for a refrigeration cycle. The refrigerating apparatuses of this kind are used as air conditioners for air conditioning in rooms by indoor units in which the user side circuits are provided, for example.
The refrigerating apparatuses of this kind are grouped into two of: one performing the expansion stroke of the refrigeration cycle in the user side circuits with an expansion valve provided in each user side circuit; and the other performing the expansion cycle of the refrigeration cycle in the heat source side circuit with an expander provided in the heat source side circuit (see Patent Document 1, for example). The latter refrigerating apparatus is more excellent in COP (coefficient of performance) than the former one because a compressor can be driven by utilizing power generated in association with expansion of the refrigerant and recovered in the expander. In the latter refrigerating apparatus, however, the refrigerant flowing out from the expander is in a two-phase state of vapor and liquid. The refrigerant in the two-phase state receives influence of the gravity and pressure loss in moving to the user side circuits in the cooling operation to cause imbalance in the state of the supplied refrigerant (a ratio of liquid refrigerant to gas refrigerant) between the user side circuits, thereby inviting difficulty in control on cooling capacity. For example, if the installation levels of the user side circuits are different from each other, the refrigerant supplied to the upper user side circuit has a greater ratio of the gas refrigerant, so that the refrigerant goes short in the upper user side circuit, inviting difficulty in appropriate adjustment of the cooling capacity.
Patent Document 1: Japanese Patent Application Laid Open Publication No. 2003-121015